1. Field of the Invention
The subject application generally relates to a mobile device, and more particularly, relates to a mobile device for operation in multiple frequency bands.
2. Description of the Related Art
With the progress of mobile communication technology, portable electronic devices, for example, portable computers, mobile phones, multimedia players, and other hybrid functional portable electronic devices, have become more common. To satisfy the demand of users, portable electronic devices usually can perform wireless communication functions. Some functions cover a large wireless communication area, for example, mobile phones using 2G, 3G, GPS and LTE (Long Term Evolution) systems and using frequency bands of 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1575 MHz, 1900 MHz, 2100 MHz, 2300 MHz, and 2500 MHz. Some functions cover a small wireless communication area, for example, mobile phones using Wi-Fi, Bluetooth, and WiMAX (Worldwide Interoperability for Microwave Access) systems and using frequency bands of 2.4 GHz, 3.5 GHz, 5.2 GHz, and 5.8 GHz.
Traditionally, a metal element with a fixed size is used as a main body of an antenna. The metal element is half wavelength or one-fourth wavelength in length, wherein the wavelength corresponds to the desired frequency band. For durability and aesthetics, a mobile device has at least a part of the housing (e.g., the front, the back or the frame) that is made of metal. However, the metal housing has a bad impact on antenna radiation.